Actually, both answers have merits. Setting a fixed time delay may not be in your best interests as needs change with time. Any set delay to initiate the rest of the load all at once might be even more inconvenient than starting them at a time you are doing the usual "Wait for Windows".
I would consider adding an argument to "continue to wait? Y/N " to the batch if you have a lot of items in it. Or you could let it be an automatic timed extension based on activity. (i.e. wait for a time of no keyboard activity to proceed). Either way, unless you do this on the whole lot (each as a separate timed action) you may find that running it all 5 minutes after you boot-up to be just as bad or even worse than running it all before you get started.
I think if these are all absolutely necessary it might be best to put them in a sequence with 1 at a time running each then checking to see if still no activity then running the next. Of course, only you know which are needed on startup. Some may not be needed at all for certain quick on/off episodes. If placed in the correct order, those would never be reached before you power down.
Another possibility is to tie the loading to the need for what is loaded. If you are not going on the Internet or using email or other “high risk” activity, you might consider not loading your AV software. Adding the command to "Run this first if not already running" to those activities could give you a significant increase in speed for local gaming or anything else that did not need to be checked and rechecked for every move. Just tie the startup to the program that needs it.
Another option to consider would be setting as many as can be done to "run as a service" as this usually seems to take less time to become active than running a normal "start the program" sequence.
FYI there is a very useful utility I have used and given to many people over the years called "StartMan" Easily found with Google and Free and I am sure there are others. It works with every version of Windows I have ever tried from Win98 to Win7. It will let you have a lot more control over your Startup programs without having to make any permanent changes to your Startup configuration and easily undo those that are not productive.